A broadcasting network comprises in a known manner a series of relay stations that receive a signal broadcast by an upline station or front-end transmitting station and propagate it to downline stations and/or a receiver such as a television set. The area covered by the broadcast signal of course depends on the number of relay stations and their geographical distribution.
The broadcast signals are most often multiplexed signals comprising one or more audio and/or video and/or data components. The audio and/or video components can, for example, be relative to radio or television programs. The data are for example user data, intended for a user receiving the broadcast signal. The data can also be control data sent to network equipment receiving the broadcast signal, such as relay stations, television set-top boxes, etc. The audio, video and user-data components have no particular meaning for the equipment of the broadcasting network. The control data, however, control the operation, define a setting, etc., of the equipment to which they are sent.
The broadcasting network is generally supplemented by a remote management network to monitor and remotely control the equipment of the broadcasting network. To do this, the equipment items of the broadcasting network equipped with an appropriate communication interface are connected to a management device via an external communication network, such as a telephone network.
A monitoring network is most often provided as a complement, notably with the aim of monitoring the quality of the broadcast signal (detecting signal degradation), and restoring quality if necessary. In a known manner, such a monitoring network comprises a set of metrological devices installed at strategic points of the broadcasting network, for example near certain relay stations. All the metrological devices are connected to a supervising device via an external communication network (a telephone network for example). The monitoring network supervising device and the management device of the remote management network can be one and the same device, each fulfilling all the functions of the other.
FIG. 1 shows a simplified diagram of a monitoring network comprising a supervising device 110 and two measuring devices 120, 130 for monitoring a broadcast signal 100. A monitoring network such as that shown in FIG. 1 is mounted in a star arrangement. The supervising device controls all the metrological devices which, when polled, return information on the quality of the signal broadcast in the geographical zone they monitor. The broadcasting network supervising device federates all the metrological devices which, either at their own initiative or on request, can communicate information to it. More generally, the supervising device manages the monitoring network as a whole by ensuring the following two main functions: a metrological device control function (asking the metrological devices for information, adjusting a metrological device, etc.) and an information and alarm processing function (utilization of the received information, feeding back information to a person responsible for the broadcasting network, etc.).
As discussed above, monitoring a broadcasting network—as it is currently performed—requires the construction of a monitoring network in parallel with the broadcasting network to be monitored, which adds (in terms of either connections or load) to the remote management network associated with the broadcasting network. This increases the installation cost of the broadcasting network accordingly.
Seeking to reduce installation costs has led to the use of an external communication network (a telephone network for example). Although this reduces costs, it nevertheless leads to technical difficulties due essentially to the fact that communication routing times over an external network are poorly controlled. This approach does not, for example, permit reliable synchronization or coordination of the operation of several metrological devices. Lastly, the links between the metrological devices of the monitoring network forcibly pass via the central supervising device, and therefore via the external communication network.